1794-IR8 RTD Module scaling???

dgalenski

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• Dec 16, 2004

• #1

I have a 1794 IR8 module I just installed on a cooling tower. It a PT100 RTD and I am returning a reading of 998 decimal. I don't know if I need to do some scaling or what??? It is about 25F outside and it is reading the air right now. Any help?????

 

mgvol

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• Dec 16, 2004

• #2

Is this Remote I/O off a PLC-5 or SLC? Or is it FlexLogix?

 

mgvol

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• Dec 16, 2004

• #3

If you are using as Rem I/O off a SLC, use the SCP instruction (if available w/CPU you're using) or SCL. If a Logix platform, in ladder logic you have to do a CPT instruction. In FBD logic, use the SCL instruction.

 

dgalenski

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• Dec 16, 2004

• #4

Thanks!!!

This is flex I/O off of a PLC5. If I have to scale this myself, what is the range that this card returns to the data table???

 

mgvol

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• Dec 16, 2004

• #5

I can't seem to locate an IR8 manual on the AB web-site, but I imagine the raw data would be 0 to 32767.

 

Kim Gold

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• Dec 16, 2004

• #6

The manual is located at:

1794-IR8 Manual

You must setup scaling as degrees C or F or -32768 to 32767 or 0 - 65535. If setup as degrees C, it will read in 0.1 degrees C.
If setup as degrees F, it will read in 0.1 degrees F.
If setup one of the other 2 ways you will need to scale result.

See chapter 4 for configuration/

Kim